Study on the Longitudinal Displacement Regularity of an Asymmetric Cable-Stayed Bridge with a Hybrid Girder Affected by Temperature

摘要

To investigate the influence of temperature on the longitudinal displacement of an asymmetric cable-stayed bridge with a hybrid girder, a finite-element system (FES) of the bridge and a simplified system of the girder and bearings in the pylon area were established. The systems were based on a cable-stayed bridge with a hybrid girder during the period after the closure of the midspan and before opening to traffic. The bearing reaction of the piers and the unbalanced force in the horizontal direction in the pylon area were calculated according to the displacement bearing data collected in the case of drastic temperature changes for 24 h. The results of the entire bridge system were substituted into the simplified system for calculation. The displacement bearing data were collected and compared with 24 h onsite results. The results indicate a linear relationship between the longitudinal displacement of the girder to the side span and the temperature of the girder. A hysteresis effect of longitudinal displacement of the concrete girder to the side span with a change in the temperature, which satisfies a bilinear model, was observed. A residual longitudinal displacement of the concrete girder displacement to the side span was observed when the temperature returned to the initial value after 24 h of continuous observation and could not be eliminated within the 24 h observation period. These results provide a sound research basis for the study of displacement bearing regularity under vehicle action; the "rump-up" of concrete side spans in which the residual value of bearing displacement accumulates for a long period within each temperature change period; and similar engineering problems of a cable-stayed bridge with a hybrid girder.